The latch on our Bonder is very easy to accidentally slide down into the lock position. The red latch is just below the door release handle and when you grab the handle your hand can push the lock downward. My daughter's boyfriend did this a couple times when he was exiting our motorhome. Fortunately, we keep a hide a key box hidden on the frame.
Jim
2014 Fleetwood Bounder 35k
2007 VW EOS